This proposal is a continuation of our research program to establish the roles of acrosomal enzymes and microtubules in fertilization in the environment created by oviduct fluid. Microtubules of the acrosome constitute a possible delivery system for acrosomal lytic enzymes, and we have demonstrated their formation from the acrosomal matrix both in vitro and in vivo by TEM, as well as the deposition of tubulin containing structures and amorphous tubulin deposits in the sperm penetration tunnel through the zona pellucida. We have also demonstrated the presence of glycosaminoglycans in primate oviduct fluid, which markedly stimulate proacrosin autoactivation and may be a triggering mechanism for acrosin delivery by a system described in the text. Our goals include the characterization of these oviductal glycosaminoglycans, the continuation of our studies on the morphology and chemistry of acrosomal microtubules, their physiological function, and the oviduct fluid factors affecting their condensation from the acrosomal matrix. We will also determine the subcellualr localization of sperm antigens reacting with oviductal secretory IgA from normal and immunized animals.